Solid phase extraction of analytes from a liquid sample is an increasingly employed method for isolating analyte impurities for analysis thereof. For example, U.S. Environmental Protection Agency Method 525.1 (Rev. 2.2), 1988, sets forth a method for the determination of organic compounds in drinking water by liquid-solid phase extraction and describes apparatus typically used for such methodology. The apparatus described therein is typical of the apparatus used in the art not only for the isolation of analytes from drinking water but for isolating analytes from other liquid samples using solid phase disc membranes.
Such prior art apparatus typically includes a vacuum/exhaust line connected to a collection flask. The collection flask will have mounted in its top opening, by way of a silicone rubber stopper, a sample holder. Such a sample holder generally comprises a glass frit support on which a solid phase disc membrane is placed and a glass sample holder is then clamped over the disc membrane by means of a metal clamp. Such apparatus is beset by many disadvantages and drawbacks.
The clamp is a generally inadequate means to provide a satisfactory seal around the disc membrane being held between the glass sample holder and glass frit support member and results in loss of analyte around the edges of the disc membrane and contamination of the work area. In the prior art apparatus the extraction solvent and analyte cannot be collected in a separate easily removable, collection vessel. In order to run multiple liquid samples, multiple apparatus set-ups of the type described must be built. The methodology resulting from the use of such a prior art apparatus is neither satisfactory, effective nor efficient.
There is therefore a need for an improved system, apparatus and method for solid phase extraction of analytes from liquid samples that essentially eliminates the aforementioned drawbacks and disadvantages and provides efficient and effective means for conducting such a solid phase extraction process and to enable the operator thereof to efficiently run a plurality of sample extraction process substantially simultaneously.